Detergent dispensing apparatus



June 8, 1965 cs. E. SHERRARD 7 3,187,767

DETERGENT DISPENSING APPARATUS Filed Dec. 15, 1962 [29 INVENTOR.

T OPNEY.

United States Patent 3,187,767 DETERGENT DISPENSING APPARATUS George E.Sherrard, Cambridge, Ohio, assignor to Calgon Corporation, a corporationof Pennsylvania Filed Dec. 13, 1962, Ser. No. 244,339 2 Claims. (Cl.137-268) This invention relates to methods and apparatus for dispensingdry granulated detergents into dishwashing machines. 1

Prior to the present invention, it was the widespread practice incommercial, i.e. restaurant dishwashing to add dry granulateddishwashing compositions to the machine by hand in a more or lessuncontrolled manner. Commercial dishwashing machines are often equippedwith inexpensive conductivity meters which sound or light an alarm whenthe concentration of dissolved solids, generally proportional to theconcentration of detergent, in the water is reduced below apredetermined minimum level. On observing the alarm, the operator addsthe proper amount of dry detergent. However, in many instances, thewashing operation is still not properly controlled, either because theoperator is busy and does not observe the alarm or because he may addmore or less detergent than is necessary.

Automatic and semiautomatic devices have been devised for controllingthe addition of liquid detergents to dishwashers. Most of these alsoemploy conductivity meters. See, for example, US. Patents 2,593,825 and2,687,139. When the signal representing conductivity (or the reciprocalof the electrical resistance of the dishwater) reaches a predeterminedvalue, a valve is opened or other means are activated for introducingthe concentrated liquid detergent into the machine until the properconductivity is reestablished.

Until the present invention, no satisfactory device was known forautomatically or semi-automatically dispensing a detergent from itsoriginal package in the form of a dry powder or granulated composition,to maintain a desired dissolved concentration in the dishwasher or otherplace of use. I have invented such a method and device. My preferredapparatus is illustrated in FIGURE 1, which shows the dry detergentcontainer, plumbing connections thereto, electrical circuitry of theconductivity meter, and valve means automatically responsive thereto.FIGURE 2 is a circuit diagram of the conductivity apparatus preferred inmy invention. FIGURE 3 is a detailed illustration of the preferredfitting and dissolving device for the dry detergent container.

In FIGURE 1, the dry detergent 1 is located in a closed container 2having a fitting 3 which accommodates incoming water conduit 4 anddistributor 5. Distributor 5 extends nearly to the bottom of container 2and is perpendicular thereto. Best results are obtained when thedistance 6 between the lower end of distributor 5 and the bottom of thecontainer is from about to about 1 inch. If this distance is notmaintained, incoming water under normal or reduced water supply pressurewill not dissolve the detergent around the edge of the bottom of thecontainer.

Container 2 is also fitted at 7 with outgoing conduit 12 leading todishwasher 8. Conductivity cell 9 is immersed in the water of thedishwasher, and is electrically connected to conductivity meter 10,which in turn is connected so as to energize solenoid valve 11 when theconductivity of the dishwasher is not in the proper range. Solenoidvalve 11 operates to open or shut ofi the flow of water from a source 13into container 2 accordingly.

FIGURE 2 is a circuit diagram of my preferred conductivity meter andrelay operable thereby. In this circuit, power from source 20 isintroduced through transformer 21, to bridge 22. Bridge 22 comprisesfixed resistors 23 and 24, normally adjustable resistor 25 andconductivity cell 26. The output of the bridge is transmitted throughtransformer 27 to thyratron 28, where it controls the flow of current tosolenoid-operated relay 29. When the resistance reaches a predeterminedmaximum, indicating that the alkalinity of the dishwater is below thedesired minimum, the thyratron causes the relay to operate, completingthe circuit to valve 30, which is then opened to permit the flow ofwater into the container of granulated detergent.

FIGURE 3 illustrates the dissolving device in detail. The top 41 of thecontainer or drum of detergent is fitted with a plastic cup 40 includingan orifice 42 having threads 43. Washer or gasket 44 seats on ahorizontal circumferential rim 45. Plastic fitting insert 46 is placeddirectly on washer 44. It is a solid disc of plastic having two threadedholes 47 and 48 into which fittings 49 and 50 are inserted. Fittings 49and 50 are adjusted to receive water pipes or tubing.

Distributor 5 is a hollow tube which communicates with fitting 49 and asexplained with reference to FIGURE 1, extends nearly to the bottom ofthe container. It is preferably provided with horizontal slits 51 and52. The tip 53 may be closed or partly open. Slits 51 and 52 are no morethan an inch from the bottom of the container, preferably no more thanabout one-half inch. Efliciency maybe improved by inclining themslightly downward (i.e. 57 off the horizontal) directly toward the outeredge of the container bottom.

Slits 51 and 52 may be replaced by one or more orifices oriented indownward, horizontal, or partly downward, partly horizontal directions.If more than a few small orifices are used, they should be disposed toemit jets of water more or less radially so that the entirecircumference of the container bottom will be reached. If only oneorifice is used, it should be large and directed at the container floor.Orifices directed upwardly do not efiiciently serve my purposes. In nocase should either horizontal or downward-directed orifices be confinedto an area of the distributor more than an inch from the containerbottom.

The operator will know the container is empty when the conductivityfails to be restored after the device dispenses for an abnormally longperiod. A new container may then very easily be installed.

It will be apparent to those skilled in the art that more or lessconcentrated solutions of detergent will be dispensed with my apparatusat different stages in the removal of the detergent from the container,and depending on the temperature of the water, the pressure, length oftime the valve is open, composition of the detergent, etc. However,regardless of such variables, my device will deliver the correct amountof detergent since it is measured by conductivity.

A semi-automatic system can be employed simply by replacing valve 30(FIG. 2) or 11 (FIG. 1) with a warning bell, light or the like. Theoperator will then turn a valve manually to admit detergent to thedishwasher until the desired conductivity is restored.

The composition of the detergent is significant in the normal use of myinvention. Not only should its overall solubility be in a range whichlends itself to practical use, but there must be no ingredients whichare appreciably more or less soluble than the other ingredients. Inorder to assure that the proper detergent mixture is entering thedishwasher at all times, the ingredients should dissolve atapproximately the same rates. Examples of compositions which areexcellent in my invention are those described in US. Patent 2,756,214. Acomposition consisting essentially of from about 20% by weight to aboutby weight sodium tripolyphosphate together with 3. from about80% toabout 20% by weight hydrated chlorinated trisodium orthophosphate isexcellent for use in my invention.

It will be apparent to those familiar withthe art that my inventioncomprises a new detergent package. The package consists of a closedcontainer filled with dry powdered or granular detergent and having aperpendicular tubular distributor substantially as described. 1

Having thus described my invention, it is to be distinctly understoodthat the invention is not limited to the examples and illustrationsgiven herein, but may be otherwise varied within the scope of thefollowing claims.

1. A package of dry detergentv suitable for dispensing detergent ofsubstantially constant composition in the dissolved form directly into adishwasher in response to a conductivity control, comprising a closedcylindrical container, detergent therein consisting essentially of about20% to about 80% sodium tripolyphosphate and about.

80% to about 20% chlorinated trisodium orthophosphate, a fixture in thetop of said container including outlet means and inlet means comprisinga tubular Water distributor adapted to be connected to an external watersource and extending downwardly to a point near the bottom of saidcontainer, said distributor having at least two orifices for causing theejection of water in different directions approximately parallel to thebase of said container.

2. The combination comprising ,7 (a) a package of dry detergent suitablefor dispensing detergent of substantially constant composition in thedissolved form directly into a dishwasher in response to a conductivitycontrol, comprising atclosed cylindrical container, detergent thereinconsisting essentially of about 20% to about sodium tripolyphosphate andabout 80% to about 20% chlorinated trisodium orthophosphate, a fixturein the top of said container including outlet means and inlet meanscomprising a tubular water distributor adapted to be connected to anexternal water source and extending downwardly to a point near thebottom of said container, said distributor having at least two orificesfor causing the ejection of water in difierent directions approximatelyparallel to the base of said container, and V (b) dishwater conductivityregulating apparatus for 7 measuring the conductivity of dishwatercontaining dissolved detergent delivered from said package andcontrolling the water supply to said distributor in response to saidconductivity.

References Cited by the Examiner UNITED STATES PATENTS 1,197,337 9/16Bonfield 23-267 1,350,175 8/20 O'Connor 13726-8 1,988,000 1/35 Estler23-267 2,419,845 4/47 Merrick 23-267 2,490,634 12/49 Keene 137-932,573,576 10/51 Klumb 23267 2,756,214 7/53 Albrecht 25299 M. CARYNELSON, Primary Examiner.

MARTIN P. SCHVJADRGN, Examiner.

1. A PACKAGE OF DRY DETERGENT SUITABLE FOR DISPENSING DETERGENT OFSUBSTANTIALLY CONSTANT COMPOSITION IN THE DISSOLVED FORM DIRECTLY INTO ADISHWATER IN RESPONSE TO A CONDUCTIVITY CONTROL, COMPRISING A CLOSEDCYLINDRICAL CONTAINER, DETERGENT THEREIN CONSISTING ESSENTIALLY OF ABOUT20% TO ABOUT 80% SODIUM TRIPOLYPHOSPHATE AND ABOUT 80% TO ABOUT 20%CHLORINATED TRISODIUM ORTHOPHOSPHATE, A FIXTURE IN THE TOP OF SAIDCONTAINER INCLUDE OUTLET MEANS AND INLET MEANS COMPRISING A TUBULARWATER DISTRIBUTOR ADAPTED TO BE CONNECTED TO AN EXTERNAL WATER SOURCEAND EXTENDING DOWNWARDLY TO A POINT NEAR THE BOTTOM OF SAID CONTAINER,SAID DISTRIBUTOR HAVING AT LEAST TWO ORIFICES FOR CAUSING THE EJECTIONOF WATER IN DIFFERENT DIRECTIONS APPROXIMATELY PARALLEL TO THE BASE OFSAID CONTAINER.